Hakai overexpression effectively induces tumour progression and metastasis in vivo.

At early stages of carcinoma progression, epithelial cells undergo a program named epithelial-to-mesenchymal transition characterized by the loss of the major component of the adherens junctions, E-cadherin, which in consequence causes the disruption of cell-cell contacts. Hakai is an E3 ubiquitin-ligase that binds to E-cadherin in a phosphorylated-dependent manner and induces its degradation; thus modulating cell adhesions. Here, we show that Hakai expression is gradually increased in adenoma and in different TNM stages (I-IV) from colon adenocarcinomas compared to human colon healthy tissues. Moreover, we confirm that Hakai overexpression in epithelial cells drives transformation in cells, a mesenchymal and invasive phenotype, accompanied by the downregulation of E-cadherin and the upregulation of N-cadherin, and an increased proliferation and an oncogenic potential. More importantly, for the first time, we have studied the role of Hakai during cancer progression in vivo. We show that Hakai-transformed MDCK cells dramatically induce tumour growth and local invasion in nude mice and tumour cells exhibit a mesenchymal phenotype. Furthermore, we have detected the presence of micrometastasis in the lung mice, further confirming Hakai role during tumour metastasis in vivo. These results lead to the consideration of Hakai as a potential new therapeutic target to block tumour development and metastasis.

Proteomic Analysis of the E3 Ubiquitin-Ligase Hakai Highlights a Role in Plasticity of the Cytoskeleton Dynamics and in the Proteasome System.

Carcinoma, the most common type of cancer, arises from epithelial cells. The transition from adenoma to carcinoma is associated with the loss of E-cadherin and, in consequence, the disruption of cell-cell contacts. E-cadherin is a tumor suppressor, and it is down-regulated during epithelial-to-mesenchymal transition (EMT); indeed, its loss is a predictor of poor prognosis. Hakai is an E3 ubiquitin-ligase protein that mediates E-cadherin ubiquitination, endocytosis and finally degradation, leading the alterations of cell-cell contacts. Although E-cadherin is the most established substrate for Hakai activity, other regulated molecular targets for Hakai may be involved in cancer cell plasticity during tumor progression. In this work we employed an iTRAQ approach to explore novel molecular pathways involved in Hakai-driven EMT during tumor progression. Our results show that Hakai may have an important influence on cytoskeleton-related proteins, extracellular exosome-associated proteins, RNA-related proteins and proteins involved in metabolism. Moreover, a profound decreased expression in several proteasome subunits during Hakai-driven EMT was highlighted. Since proteasome inhibitors are becoming increasingly used in cancer treatment, our findings suggest that the E3 ubiquitin-ligase, such as Hakai, may be a better target than proteasome for using novel specific inhibitors in tumor subtypes that follow EMT.

Circulating miR-200c and miR-141 and outcomes in patients with breast cancer.

BACKGROUND: The deregulation of microRNAs in both tumours and blood has led to the search for microRNAs to indicate the presence of cancer and predict prognosis. We hypothesize the deregulation of miR-200c/miR-141 in the whole blood can identify breast cancer (BC), and could be developed into a prognostic signature. METHODS: The expression of miR-200c and miR-141 were examined in bloods (57 stage I-IV BC patients and 20 age-matched controls) by quantitative reverse-transcription PCR. The associations of circulating microRNAs with clinic and pathological characteristics were analysed. Their effects on survival were analysed by the Kaplan-Meier method and Cox regressions. RESULTS: MiR-200c was down regulated (P < 0.0001) in the blood of BC patients, yielded an area under the ROC curve of 0.79 (90% sensitivity, 70.2% specificity) in discriminating BC from controls. Circulating miR-141 was not discriminating. MiR-200c and miR-141 in the blood of BC patients were inversely correlated (P = 0.019). The miR-200c levels were numerically higher in stage IV and tumours with lower MIB-1. MiR-141 was significantly higher in the blood of patients with stage I-III, lymph node metastasis, and HER2 negative tumours. High blood expression of miR-200c and/or low expression of miR-141 was associated with unfavourable overall survival (hazard ratio, 3.89; [95% CI: 1.28-11.85]) and progression-free survival (3.79 [1.41-10.16]) independent of age, stage and hormonal receptors. CONCLUSIONS: Circulating miR-200c and miR-141 were deregulated in BC comparing with controls. Furthermore, miR-200c and miR-141 were independent prognostic factors and associated with distinct outcomes of BC patients.

Circulating miR-200c as a diagnostic and prognostic biomarker for gastric cancer.

BACKGROUND: MicroRNAs are aberrantly expressed and correlate with tumourigenesis and the progression of solid tumours. The miR-200 family determines the epithelial phenotype of cancer cells and regulates invasiveness and migration. Thus, we hypothesised that the quantitative detection of the miR-200 family as epithelial-specific microRNAs in the blood could be a useful clinical biomarker for gastric cancer (GC). METHODS: We initially validated the expression levels of miR-200a, 200b, 200c and 141 in GC cell lines (n = 2) and blood from healthy controls (n = 19) using real-time quantitative reverse transcription PCR (qRT-PCR). The microarray expression profiles of the miR-200 family in 160 paired samples of non-tumour gastric mucosae and GC were downloaded through ArrayExpress and analysed. MiR-200c was selected for clinical validation. The qRT-PCR prospective assessment of miR-200c was performed using 67 blood samples (52 stage I-IV GC patients and 15 controls); the area under the receiver operating characteristic curve (AUC-ROC) was estimated. The Kaplan-Meier and Breslow-Wilcoxon tests were used to assess the correlation of miR-200c with overall and progression-free survival (OS and PFS). Multivariate analyses were performed using the Cox model. RESULTS: The miR-200c blood expression levels in GC patients were significantly higher than in normal controls (p = 0.018). The AUC-ROC was 0.715 (p = 0.012). The sensitivity, specificity and accuracy rates of 65.4%, 100% and 73.1%, respectively, were observed. The levels of miR-200c in the blood above the cutoff defined by the ROC curve was found in 17.6% of stage I-II GC patients, 20.6% of stage III patients and 67.7% of stage IV patients (p < 0.001). The miR-200c expression levels were not associated with clinical or pathological characteristics or recent surgical procedures. There was a correlation (p = 0.016) with the number of lymph node metastases and the increased expression levels of miR-200c in blood were significantly associated with a poor OS (median OS, 9 vs 24 months; p = 0.016) and PFS (median PFS, 4 vs 11 months; p = 0.044). Multivariate analyses confirmed that the upregulation of miR-200c in the blood was associated with OS (HR = 2.24; p = 0.028) and PFS (HR = 2.27; p = 0.028), independent of clinical covariates. CONCLUSIONS: These data suggest that increased miR-200c levels are detected in the blood of gastric cancer patients. MiR-200c has the potential to be a predictor of progression and survival.

Evaluation of the adenocarcinoma-associated gene AGR2 and the intestinal stem cell marker LGR5 as biomarkers in colorectal cancer.

We aim to estimate the diagnostic performances of anterior gradient homolog-2 (AGR2) and Leucine-rich repeat-containing-G-protein-coupled receptor 5 (LGR5) in peripheral blood (PB) as mRNA biomarkers in colorectal cancer (CRC) and to explore their prognostic significance. Real-time PCR was used to analyze AGR2 and LGR5 in 54 stages I-IV CRC patients and 19 controls. Both mRNAs were significantly increased in PB from CRC patients compared to controls. The area under the receiver-operating characteristic curves were 0.722 (p = 0.006), 0.376 (p = 0.123) and 0.767 (p = 0.001) for AGR2, LGR5 and combined AGR2/LGR5, respectively. The AGR2/LGR5 assay resulted in 67.4% sensitivity and 94.7% specificity. AGR2 correlated with pT3-pT4 and high-grade tumors. LGR5 correlated with metastasis, R2 resections and high-grade. The progression-free survival (PFS) of patients with high AGR2 was reduced (p = 0.037; HR, 2.32), also in the stage I-III subgroup (p = 0.046). LGR5 indicated a poor prognosis regarding both PFS (p = 0.007; HR, 1.013) and overall survival (p = 0.045; HR, 1.01). High AGR2/LGR5 was associated with poor PFS (p = 0.014; HR, 2.8) by multivariate analysis. Our findings indicate that the assessment of AGR2 and LGR5 in PB might reflect the presence of circulating tumor cells (CTC) and stem cell like CTC in CRC. Increased AGR2 and LGR5 are associated with poor outcomes.

Prognostic impact of disseminated tumor cells and microRNA-17-92 cluster deregulation in gastrointestinal cancer.

The presence of tumor cells in the bone marrow (BM) could be relevant to identifying high risk of disease progression and death in gastrointestinal cancer. However, the molecular profile associated with disseminated tumor cells (DTCs) homing to the BM has yet to be defined. MicroRNAs (miRNA) play key roles in cellular processes implicated in cancer. Thus, we investigated in 38 patients with colorectal, gastric or pancreatic cancer whether the presence of BM-DTCs is associated with a specific miRNA tumor profile and analyzed their potential prognostic impact. DTCs were detected by immunocytochemistry and anti-cytokeratin antibodies in 42.1% of the patients. miRNAs were isolated from formalin-fixed, paraffin-embedded tumors. qRT-PCR was used for miRNA profiling. No significant associations were found among DTC detection and miRNA deregulation. Kaplan-Meier curves demonstrated significantly reduced progression-free survival (PFS) and overall survival (OS) in the DTC-positive patients. Although miR-21 was upregulated in 90.6% of the tumors, no associations with outcomes were found. miR-17 and miR-20a (miRNA-17-92 cluster) were upregulated in 33.3 and 42.4%, respectively. Upregulation of both was correlated and found in 30.3%. Univariate analysis shows that increasing values for miR-20a were significantly associated with reduced PFS (HR 1.022; p=0.016) and OS (HR 1.027; p=0.003). In multivariate Cox models, DTC positivity (HR 4.07; p=0.005) and miR-17 overexpression (HR 2.11; p=0.003) were significantly associated with a higher risk of disease progression. The presence of DTCs in the BM (HR 3.98; p=0.010) and a miR-17 overexpression (HR 2.62; p<0.001) were also associated with a risk of death. Our study suggests that the presence of BM-DTCs and the upregulation of the miR-17-92 cluster in tumors are both significant but independent prognostic markers in gastrointestinal cancer patients.

Evaluation of plakophilin-3 mRNA as a biomarker for detection of circulating tumor cells in gastrointestinal cancer patients.

BACKGROUND: This study aims to assess Plakophilin-3 (PKP3) as a surrogate biomarker of circulating tumor cells in patients with gastrointestinal cancer. METHODS: The primary aim is to estimate the diagnostic accuracy of PKP3 real-time reverse transcriptase-PCR in blood. Receiver operating characteristic curves were constructed. Correlations between the blood PKP3 levels and the clinicopathologic features of the study subjects were analyzed. Logistic regression was used to predict outcomes based on PKP3. RESULTS: Sixty-four patients with gastrointestinal cancer and 23 controls were included. The mean relative PKP3 mRNA expression was 48.45 in cancer patients and 2.8 in controls (P < 0.0001). Comparing the PKP3 levels in patients and controls, the area under the curve was 0.852 (95% confidence interval, 0.76-0.94; P < 0.0001) in receiver operating characteristic analysis. A higher blood level of PKP3 mRNA was associated with a more advanced stage (P = 0.025), pT(3-4) tumors (P = 0.028), metastasis (P = 0.021), and residual (R2) disease (P = 0.037). Higher PKP3 mRNA was associated with the risk of cancer progression and death (odds ratio, 3.875; 95% confidence interval, 1.781-8.430; P = 0.001). CONCLUSIONS: Increased PKP3 mRNA was detected in the blood of gastrointestinal cancer patients. Significant correlations were found with advanced stage, pT(3-4), metastatic disease, and the residual disease status. PKP3 mRNA in blood was associated with the risk of cancer progression and death. IMPACT: PKP3 mRNA can be used as a marker of subclinical disease in gastrointestinal cancer and thus holds potential clinical relevance as a predictor for disease outcome.

Bioinformatics approach to mRNA markers discovery for detection of circulating tumor cells in patients with gastrointestinal cancer.

BACKGROUND: Detection of tumor cells in the blood, or minimal deposits in distant organs as bone marrow, could be important to identify cancer patients at high risk of relapse or disease progression. Quantitative polymerase chain reaction (PCR) amplification of tissue or tumor selective mRNA is the most powerful tool for the detection of this circulating or occult metastatic cells. Our study aims to identify novel gastrointestinal cancer-specific markers for circulating tumor cell detection. METHOD: Phase I preclinical study was performed by means of computational tools for expression analysis. In silico data were used to identify and prioritize molecular markers highly expressed in gastrointestinal cancers but absent in hematopoietic-derived libraries. Selected genes were evaluated by means of qRT-PCR in gastrointestinal cancer and hematopoietic cell-lines, normal human bone marrows and bloods, tumor tissue, and blood from cancer patients. RESULTS: Novel and known mRNA markers for circulating tumor cell detection in gastrointestinal cancer have been identified. Among all the genes assessed, PKP3, AGR2, S100A16, S100A6, LGALS4, and CLDN3 were selected and assays based on blood qRT-PCR were developed. Reliably qRT-PCR assays for the novel targets plakophilin 3 (PKP3) and anterior gradient-2 (AGR2) to identify blood-borne cells in cancer patients were developed. CONCLUSIONS: Novel and known gastrointestinal-specific mRNA markers for circulating tumor cells have been identified through in silico analysis and validated in clinical material. qRT-PCR assay targeted to PKP3 and AGR2 mRNAs might be helpful to detect circulating tumor cells in patients with gastrointestinal cancer.